Testing general relativity with binary black holes: a study on the sensitivity requirements for future space-based detectors

TL;DR

This paper assesses the sensitivity enhancements needed in future space-based gravitational wave detectors to detect signals indicating deviations from general relativity, focusing on specific black hole merger signals.

Contribution

It quantifies the noise reduction requirements for detectors like TianQin, LISA, and $$Ares to observe beyond-GR effects in black hole mergers.

Findings

Detection sensitivity improvements of 4-9 orders of magnitude are needed for certain signals.

The required sensitivity depends heavily on the target signals and black hole binary population models.

Different target signals demand varying levels of detector noise reduction.

Abstract

We study the sensitivity required for a future space-based detector to search for beyond general relativity effect in gravitational wave detection. To do this, we use the current design of TianQin, LISA, and $\mu$Ares as starting points, and study how their key noise parameters should be improved to adequately detect some target signals, for which we choose a nonlinear ringdown mode, displacement memory, and a putative beyond general relativity signal, all from the merger of massive black hole binaries. We find that the required improvements are strongly dependent on the choice of the target signals and the population model of massive black hole binaries, and $4-9$ orders of magnitude improvement will be needed in the most demanding detection scenarios.